1. Field of the Invention
The present invention relates to a detaching driving mechanism for a comber.
2. Description of the Related Art
The lap combing cycle of a comber includes the steps of combing the front end of a lap gripped at the rear end thereof by a nipper of a combing cylinder, advancing the nipper to move the combed fleece to detaching rollers, and reversing the detaching rollers in synchronism with the advancement of the nipper. This action reverses fleece pulled out from the lap in the preceding combing cycle so that the fleece combed in the present combing cycle overlaps the fleece combed in the preceding combing cycle, rotating the detaching rollers in the normal direction to pull off the combed fleece combed in the present combing cycle from the nipper, and combing the rear end of the fleece with a top comb. The rotation of the detaching rollers in the normal and reverse directions is transferred from the cylinder shaft to synchronize the same therewith. That, is the detaching rollers are stopped or slightly rotated during the first half of a full turn of the cylinder shaft, and are rotated in the normal direction immediately after the rotation in the reverse direction during the second half of a full turn of the cylinder shaft.
Such a reciprocating rotational motion of the detaching rollers is produced by combining a constant-speed rotative input and a variable-speed rotative input applied to a differential gear mechanism connected to the input shaft of the detaching roller unit. The variable-speed rotative input is applied by an input means employing a cam (Japanese Examined Patent Publication (Kokoku) No. 44-17573) or an input means employing a linkage (Japanese Examined Patent Publication (Kokoku) Nos. 43-10728 and 53-15178).
The input means employing a cam can obtain an ideal curve of motion for piecing and pulling a fleece by properly designing the cam surface of the cam. Nevertheless, the cam groove of the cam is quickly abraded because the inertia of driving members for transmitting the motion of a cam follower to the detaching roller unit is concentrated on the line of contact of the cam follower and the cam groove when reversing and accelerating the detaching rollers, which produces the advancing and reversing motions, and the mechanism is also expensive because the width and shape of the cam groove must have a precise accuracy.
When the components of the input means employing a cam are operated at high operating speed, to improve the productivity, a large impact of the cam and the cam follower, when changing the direction of rotation of the detaching rollers from the reverse direction to the normal direction generates noise and vibrations, accelerates the abrasion of the cam surface, shortens the lifetime of the machine, and deteriorates the quality of the combed slivers. Therefore, the input means employing a cam is unable to operate at a high operating speed, and the productive efficiency of a machine employing such an input means is unsatisfactory.
Although a comber employing an input means using a linkage, namely, a camless comber, is able to operate at a relatively high operating speed, only motion curves H and J as shown in FIGS. 7 and 8 are possible, and thus the fleece delivered by the feed roller of the nipper cannot be fully drafted because a portion A of the curve of motion shown in the drawing, in particular, can be formed only with a large radius of curvature, and severe noise and shocks are liable to be generated. Moreover, the parts are abraded quickly and are liable to be damaged because, in a portion B in which the rotation direction is changed from the reverse direction to the normal direction, the motion of the change is sudden. Consequently, the quality of slivers of long fibers is unsatisfactory.